In the last few years, driver assistance systems have been increasingly made available to a broad user base. These systems assist drivers in performing the functions of controlling a vehicle and the intention is that in the future they will significantly improve comfort and safety in road traffic. The development of more efficient and at the same time more cost-effective sensors has enabled the field of application of driver assistance systems to be widened. This usually involves a division into longitudinal control systems and lateral control systems.
The Adaptive Cruise Control (ACC) driver assistance system assists drivers in performing the vehicle longitudinal control function. Originally, such systems were developed for use on freeways and high-quality country roads with a high speed potential. It has also been possible to extend the field of application of modern ACC systems to the low speed range and to follow-on mode travel as far as a stationary state.
In a way which is comparable to longitudinal control assistance, a driver can also be assisted by an assistance system in the performance of the lateral control function. If the area which can be traveled on is detected by a suitable sensor system, the assistance can be provided in a plurality of stages. The functionality of already available systems extends here from simple messages (Lane Departure Warning, LDW) to assisting steering interventions in situations in which the vehicle is about to exit the lane (for example “Lane Assist” in the VW Passat CC). These assistance systems orient themselves by using the lane markings which are usually sensed by means of monocular video sensor systems.
Document DE 103 43 178 A1 discloses a driver assistance system for motor vehicles which has a sensor system for sensing the traffic environment and a controller for controlling the acceleration of the motor vehicle in accordance with a predetermined longitudinal control strategy, wherein a strategy module determines in a variable fashion the longitudinal control strategy which is to be applied. In this context, the driver can use an input device to select between a number of predefined longitudinal control strategies, for example comfort, normal or dynamic, and to adapt the system behavior of the driver assistance system in accordance with his requirements.